Efficient and Environmentally friendly biodiesel production from microalgae cultures

Kurzfassung

An Italian agricultural research park has developed a method to produce vegetable oil for biodiesel conversion using microalgae cultured in seawater. The development of algal growth is based on a revolutionary system that is completely new in the world scene of algal biotechnologies. The systems can be installed in contaminated water or other marginal areas. The developer is interested in a commercial agreement with technical assistance or technical cooperation agreement.

Details

The production of biodiesel obtainable from marine microalgae is a revolutionary system, completely new in the world scene of algal biotechnologies. The system is designed to be economically competitive, the marine platforms are conceived to host thousands of culturing litres with management costs that foresee only the harvest of the algal suspension.

With a simple system to cultivate microalgae in sea water it is possible to simultaneously obtain:

1. production of oil for biofuels
2. production of natural fertilisers (dried algal biomass)
3. treatment of polluted water
4. biofixation of greenhouse gases.

When microalgae have an adequate supply of light energy and an appropriate environment, they grow with elevated conversion efficiencies of light energy, using CO2 as a source of carbon and substances present in the wastewater and/or in the gas flows (NOX, SO2) as nutrients. In suitable conditions, the algal cultures can attain production of more than 75 tons of dry biomass per year per hectare, fixing in this way more than 150 tons of CO2 and about ten tons of nitrogenous compounds. The production of algal biomass intended for use as energy can therefore be usefully combined with treatment of wastewater and with biofixation of greenhouse gases (CO2 , N2O).

Some algal strains can accumulate elevated contents of triglycerides, the lipidic portion useful for the production of biodiesel following trans-esterification. Algal cultures can be produced in sea or salt water or in wastewater, so that culture systems can be located on marginal or deteriorated land.

The production of biodiesel from microalgae cultures does not remove fertile land or resources from traditional agricultural food production and achieves fuel production that is 6-7 times greater than that obtained by agrarian production of biofuels. The algal biomass residues remaining after the extraction of the lipidic portion can be used in formulation of protein-containing feed or fertilizer.

The overall process of production/consumption should have a low and presumably "CO2 free" environmental impact (zero emission), in that the pickup of CO2 from the atmosphere in the course of chlorophyllous photosynthesis of the growing plants should be equal to or greater than the CO2 emissions to the atmosphere by the combustion of diesel engines. So such a process would be at least a practical application of the Kyoto Protocol on emissions.

Besides the low environmental impact, biodiesel also has a low impact on human health.

The possibility to capture and reuse CO2 emissions through intensive cultivation of microalgae represents an innovative and eco-compatible option to mitigate greenhouse gas emissions coming from the combustion of fossil fuels and to produce renewable bio-fuels.

With algae as the vehicle for producing oil, the yield is assumed to be 20,000 –75,000 litres/year/acre (4000m2), versus 200-500
litres/year/acre from seed plants, such as rapeseed.

These results are possible with a low level of complexity of marine platform system, which is in its simplest form made up of

1. algae cultivation tanks, exposed to sunlight
2. system for cold ultrasonication of the algae
3. system for transesterefication separation

With this type of system, placed for example at a seashore wastewater outlet, it would be possible, based on scientific studies that have been performed, to treat saltwater in lagoons. The same algae, at the end of their growth process, would be treated on site producing vegetable oil and waste biomass which, appropriately dried and chopped up, would be usable as natural fertiliser.

Innovative Aspects:
The system is completely new in the microalgal sector.
There are several distinct advantages: high production of vegetable oil for biodiesel production (the algae produce more than twice as much oil as soy), without removing arable land from food production or diverting grain or oils from food markets; additional value added from dried microalgal residue which can be used as feed or fertiliser; biofixation of greenhouse gases; the system also reduces contamination of wastewater used for culturing.